Interactive Geometry

Accurate geometry definition is critically important, and Arcis' respect for this First Rule of Processing led us to write Geom, a superb interactive front end application used for picking first breaks and for geometry generation/verification. Geom allows processors to build the strong foundation needed for high powered downstream processing.

Click below to view our Geom tool in action!

Below we showcase a sampling of some key Geom functionalities. Specifically, we discuss interactive geometry correction, crooked line binning, and map displays.

Interactive Geometry Correction

Figure 1a shows the picks for a shot from a 3D land survey. The picks are displayed by offset with a user-specified linear "refraction function" overlain in red. This refraction function serves as an important QC tool in two distinct ways. First, within the context of the shot at hand, geometry correctness is quickly confirmed by observing the pick positions relative to the refraction function line. If the picks (in blue) are tightly grouped and closely track the refraction function (in red), the geometry/patch has likely been correctly specified; on the other hand significant scattering of picks indicates a geometry problem which must be fixed by the processor. In this case, we indeed observe a high degree of scatter related to a geometry error. The error may be fixed by dragging the location/patch/receiver line to collapse the scatter as illustrated in the interactive geometry demo, and the result of this correction procedure is shown in Figure 1b.

The second main QC usage of the refraction function is for rapid identification of potential geometry errors across the survey at large, rather than within a particular shot. Specifically, for each shot a single QC value is calculated representing the difference between the first break picks and the corresponding times on the refractor function. This QC value is presented on a histogram plot for comparison with other shots (middle pane of Figures 1a and 1b). By examining relative differences in the QC values, the processor can quickly identify outlier shots whose values deviate largely from the norm. Such shots would indicate additional potential geometry errors and would warrant further investigation.

Crooked Line Binning

Figure 2: 2D Geom main window

In the case of crooked 2D lines, special attention must be paid to CMP binning. Figure 2 shows the 2D main Geom window for a very crooked line. For this data set the inconsistent station interval and the curvature of the line results in a scattering of CMPs. In order to accommodate this scattering, several steps must be taken. First, an equal CMP interval is set or calculated and is forced on the crooked line. Next, by adjusting the CMP line via a smoother, the processor works to obtain the highest most consistent fold along the crooked line.

Figure 3: Crooked line binning interface

Figure 4: Expanded view of white box shown in Figure 3

Figure 3 shows our interactive crooked line binning tool. The fold values along the line can be viewed at the top of the screen in the fold histogram. The surface location of the line is indicated in red. The yellow line represents the subsurface CMP line, and the blue dots represent the CDP scatter. Figure 4 presents an expanded view of the white box shown in Figure 3. The individual CMP bins, represented by short yellow segments running perpendicular to the CMP line, are clearly visible at this scale.

Map displays

The Geom interactive tool can produce maps of various surface and sub-surface geometry attributes. A representative sampling is shown in Figure 5 below:

Interactive Geometry

Accurate geometry definition is critically important, and Arcis’ respect for this First Rule of Processing led us to write Geom, a superb interactive front end application used for picking first breaks and for geometry generation/verification. Click here to see our Geom tool in action. (hyperlink to interactive geometry demo).

Geom allows processors to build the strong foundation needed for high powered downstream processing, and below we showcase a sampling of some key Geom functionalities. Specifically, we discuss interactive geometry correction, crooked line binning, and map displays.

Interactive Geometry Correction

Figure 1a shows the picks for a shot from a 3D land survey. The picks are displayed by offset with a user-specified linear “refraction function” overlain in red. This refraction function serves as an important QC tool in two distinct ways. First, within the context of the shot at hand, geometry correctness is quickly confirmed by observing the pick positions relative to the refraction function line. If the picks (in blue) are tightly grouped and closely track the refraction function (in red), the geometry/patch has likely been correctly specified; on the other hand significant scattering of picks indicates a geometry problem which must be fixed by the processor. In this case, we indeed observe a high degree of scatter related to a geometry error. The error may be fixed by dragging the location/patch/receiver line to collapse the scatter asillustrated in the interactive geometry demo, (hyperlink to interactive geometry demo), and the result of this correction procedure is shown in Figure 1b.The second main QC usage of the refraction function is for rapid identification of potential geometry errors across the survey at large, rather than within a particular shot. Specifically, for each shot a single QC value is calculated representing the difference between the first break picks and the corresponding times on the refractor function. This QC value is presented on a histogram plot for comparison with other shots (middle pane of Figures 1a and 1b). By examining relative differences in the QC values, the processor can quickly identify outlier shots whose values deviate largely from the norm. Such shots would indicate additional potential geometry errors and would warrant further investigation.

Crooked Line Binning

In the case of crooked 2D lines, special attention must be paid to CMP binning. Figure 2 shows the 2D main Geom window for a very crooked line. For this data set the inconsistent station interval and the curvature of the line results in a scattering of CMPs. In order to accommodate this scattering, several steps must be taken. First, an equal CMP interval is set or calculated and is forced on the crooked line. Next by adjusting the CMP line via a smoother, the processor works to obtain the highest most consistent fold along the crooked line.

Figure 3 shows our interactive crooked line binning tool. The fold values along the line can be viewed at the top of the screen in the fold histogram. The surface location of the line is indicated in red. The yellow line represents the subsurface CMP line, and the blue dots represent the CDP scatter. Figure 4 presents an expanded view of the white box shown in Figure 3. The individual CMP bins, represented by short yellow segments running perpendicular to the CMP line, are clearly visible at this scale.

Map displays

The Geom interactive tool can produce maps of various surface and sub-surface geometry attributes. A representative sampling is shown in Figure 5 below:

Figure 5a: Range-limited fold (0-1500m in this case)

Figure 5b: Actual offset associated with the near-offset trace in each bin